compiler: take some AbiMap fields private

Author: workingjubilee

compiler/rustc_abi/src/map.rs

@@ -16,9 +16,9 @@ pub struct AbiMap {
     pub rust_cold: CanonAbi,
 
     // optional architecture-specific ABIs, should always answer a certain way per-arch
-    pub efiapi: Option<CanonAbi>,
-    pub win64: Option<CanonAbi>,
-    pub sysv64: Option<CanonAbi>,
+    efiapi: Option<CanonAbi>,
+    win64: Option<CanonAbi>,
+    sysv64: Option<CanonAbi>,
 
     // optional abstract ABIs, these can be very weird
     pub stdcall: Option<CanonAbi>,